Arm Material: aluminum Arm Length: 165mm BB Type: [recommended pressfit] BB-MT500-PA, [recommended threaded] SM-BB52 Spindle: 44820 Q Factor: 175mm Shimano's new 12-speed technology makes it way to their Deore group with the M6100 crankset. This 1x crankset uses the same dynamic chain engagement technology of their pricier cranksets, in an affordable package. The two-piece design adds rigidity and therefore efficiency to your pedaling, while the direct-mount chainring makes future swaps simple.